Related papers: GK Per and EX Hya: Intermediate polars with small …
We consider the behavior of matter in the accretion column that emerges under accretion in binary systems near the surface of a white dwarf. The plasma heated in a standing shock wave near the white dwarf surface efficiently radiates in the…
We present multi-wavelength observations of the first recorded low state of the intermediate polar BG CMi. Optical monitoring of the source by members of the American Association of Variable Star Observers reveals a decrease of ~0.5 mag…
We discovered Fe $K_{\alpha}$ complex emission and pulsation in two highly variable sources (4XMM J174917.7--283329, 4XMM J174954.6--294336). The equivalent widths of 6.4 and 6.7 keV lines of 4XMM J174917.7--283329 are $99^{+84}_{-72}$ and…
Recent high-sensitivity observations reveal that accreting giant planets embedded in their parental circumstellar disks can emit H$\alpha$ at their final formation stages. While the origin of such emission is not determined yet,…
It has been shown that during the outburst of accretion activity observed in UX Ori type star RZ Psc in 2013, the accretion rate increased approximately by an order of magnitude. This means that the accretion process at the late stages of…
Quasi-spherical subsonic accretion onto slowly rotating magnetized NS is considered, when the accreting matter settles down subsonically onto the rotating magnetosphere, forming an extended quasi-static shell. The shell mediates the angular…
We present near-infrared $J$ band photometric observations of the intermediate polar WX Pyx. The frequency analysis indicates the presence of a period at 1559.2 $\pm$ 0.2 seconds which is attributed to the spin period of the white dwarf.…
We investigate the relation between the optical (g-band) and X-ray (0.5-10 keV) luminosities of accreting nonmagnetic white dwarfs. According to the present-day counts of the populations of star systems in our Galaxy, these systems have the…
The disc instability model (DIM) has been very successful in explaining the dwarf nova outbursts observed in cataclysmic variables. When, as in intermediate polars (IP), the accreting white dwarf is magnetized, the disc is truncated at the…
We report the first detailed spectroscopic observations of the recently identified intermediate polar RXJ0028.8+5917/V709 Cas. We discovered that the system shows significant EW ~ (2-4)A broad absorptions, affecting the Balmer lines from…
We present analyses of an Intermediate Polar, IGR J15094-6649, based on the archival optical data obtained from the Transiting Exoplanet Survey Satellite (TESS) and X-ray data obtained from the Suzaku, NuSTAR, and Neil Gehrels Swift…
Observations of AGNs and microquasars by ASCA, RXTE, Chandra and XMM-Newton indicate the existence of broad X-ray emission lines of ionized heavy elements in their spectra. Such spectral lines were discovered also in X-ray spectra of…
Recent advances in time-domain astronomy have led to fresh observational insights into intermediate polars, a subtype of magnetic cataclysmic variables generally accreting via a partial accretion disc. These new discoveries include…
When a white dwarf (WD) is weakly magnetized and its accretion disk is thin, accreted material first reaches the WD's surface at its equator. This matter slows its orbit as it comes into co-rotation with the WD, dissipating kinetic energy…
Observations of AGNs and microquasars by ASCA, RXTE, Chandra and XMM-Newton indicate the existence of wide X-ray emission lines of heavy ionized elements in their spectra. The emission can arise in the inner parts of accretion discs where…
Some intermediate polars show outbursts that are much shorter than those observed in normal dwarf novae, and whose origin has remained unelucidated for a long time. We examine here the case of V1223 Sgr, an intermediate polar that showed a…
When an accreting star is close to rotational equilibrium between the dipole component of the stellar magnetic field and the accretion disk, the star's rotation rate is roughly of the order of the Keplerean rotation rate at the inner…
Magnetic cataclysmic variables provide a natural laboratory for studying how accretion interacts with compact-object magnetospheres and generates stochastic variability. We present an optical variability study of the intermediate-polar…
A review of wind accretion in high-mass X-ray binaries is presented. We focus attention to different regimes of quasi-spherical accretion onto the neutron star: the supersonic (Bondi) accretion, which takes place when the captured matter…
We here examine the conditions of the two-phase disk model under which magnetic flares arise above the cold accretion disk due to magnetic buoyancy and produce X-rays via Comptonization of the disk's soft radiation. We find that the disk's…